INT 61 - Banyan VINES - SET DRIVE CONNECTION                                    
	AX = 0004h subfn 0001h
	DS:DX -> request block (see #03402)
Return: AX = status (0000h,0037h,0038h,0055h) (see #03400)
Desc:	Maps the specified file service to a DOS drive letter
Note:	If an empty service name is specified, an existing connection will
	  be removed
SeeAlso: AX=0004h/SF=0002h


Format of VINES Function 0004h/Subfunction 0001h request block:
Offset	Size	Description	(Table 03402)
 00h	WORD	0001h
 02h	BYTE	drive number (0=default, 1=A, ...)
 03h 16	BYTEs	reserved
 13h 64	BYTEs	null-terminated file service name
 53h  5	BYTEs	reserved